.clear:after {
  display: block;
  clear: both;
  content: "";
}
.left {
  float: left;
}
.rigth {
  float: right;
}
header {
  width: 100%;
  max-width: 640px;
  height: 0.128rem;
  background: #1448AE;
  line-height: 128px;
  color: #fff;
  position: relative;
  margin: 0 auto;
}
header .black {
  width: 40px;
  height: 40px;
  display: inline-block;
  position: absolute;
  left: 0.21rem;
  top: 50%;
  -webkit-transform: translate(0, -50%);
      -ms-transform: translate(0, -50%);
          transform: translate(0, -50%);
  background: url("../../images/icon/back.png") 0px 0px no-repeat;
  background-size: 100% 100%;
}
header span {
  position: absolute;
  left: 50%;
  -webkit-transform: translate(-50%, 0);
      -ms-transform: translate(-50%, 0);
          transform: translate(-50%, 0);
  font-size: 0.16rem;
  letter-spacing: 0.051rem;
}
